CN1495277A - Cold-set carbon-contained pellet sponge-iron production uquipment - Google Patents

Abstract

The present invention relates to a production equipoment of spongy iron in the metallurgical field. It is a complete set of interlinked cold-setting carbon-containing pellet spongy iron productino equipment mainly formed from 12 fixed bed reduction furnaces and material-conveying device. The equipment not only can solve three difficult problems of the pulverization, suspension and reoxidation of said cold-setting carbon-containing pellet in high-temp. reduction process at 1200 deg.C, but also can make the procedures of pellet transportation, carging and discharge be simple.

Description

Cold-setting carbon-containing pellet sponge iron production device

The invention belongs to the field of metallurgy, and discloses a special device for producing sponge iron by utilizing cold-set carbon-containing pellets.

At present, a sponge iron production method adopting a natural gas cracking method to producereducing gas and equipped with a reducing furnace is mostly adopted in the world, but the method is not suitable for areas lacking natural gas resources; although the method for producing the sponge iron in the rotary kiln by using the coal as the reducing agent solves the problem of natural gas shortage, the method still has the defects of large equipment investment, long reduction time and high energy consumption; 0112222.1 discloses a method for producing sponge iron by heating carbon-containing pellets with high-temperature gas, which greatly improves the production efficiency, but has the disadvantages of high labor, electricity and time consumption in the aspects of mechanical discharging and charging of an interlinked fixed bed reduction furnace and transportation before and after charging, and the method for cooling and reducing the pellets with nitrogen gas is not beneficial to the recovery of heat energy.

The invention aims to provide a production device of cold-setting carbon-containing pellet sponge iron, which saves labor and time, is simple and smooth, and is efficient and energy-saving in charging and discharging and pellet transportation.

The invention relates to a interlinked sponge iron production system which is composed of 12 fixed bed reduction furnaces with the same structure (the number of the reduction furnaces can be increased or decreased according to the output and the volume of a single furnace) and is controlled by a high-temperature valve through the connection of heat-insulating pipelines. The top of the fixed bed reduction furnace is provided with a combustion chamber, so that the high-temperature coal gas entering the reduction furnace is partially oxidized by a method of adding a proper amount of oxygen to increase the temperature, so as to meet the requirement of the carbon-containing pellets on the reduction temperature of 1100-1200 ℃. The coal gas continuously passes through a plurality of reducing furnaces from high temperature to low temperature, and plays roles of high-temperature direct reduction, low-temperature indirect reduction and pellet preheating on carbon-containing pellets in the furnaces. Through the procedures, the temperature of the coal gas is gradually reduced, and the coal gas is recycled as cooling coal gas after being purified, so that the aim of saving energy is fulfilled. And a lifting mechanism for loading and discharging materials is arranged at the bottom of the reduction furnace so as to integrally load and discharge the combined reaction tank loaded with the pellets into a furnace hearth. The 12 reaction tanks are divided into two groups and longitudinally arranged, the bottom of each group of reaction tanks is provided with a track for the operation of a transport vehicle, two ends of the track are respectively provided with a groove, and a transverse ferry vehicle which operates along the track is arranged in the groove. In the production system, the pellets that have completed the reduction process are still in a high-temperature state, so the high-temperature pellets are cooled by using low-temperature gas. And the low-temperature coal gas passes through a plurality of reduction furnaces to be cooled, the pellets are gradually cooled from low temperature to high temperature until the temperature is close to the normal temperature, and then the pellets are discharged out of the furnace after being replaced by nitrogen. The temperature of the low-temperature coal gas is gradually raised due to the cooling of the pellets, and the low-temperature coal gas finally returns to the coal gas generating device and then returns to the reducing furnace for recycling after being heated by the next step, so that the waste heat of the pellets is recycled, and the purpose of saving energy is realized. In the device, the whole reaction process from the charging of the carbon-containing pellets to the discharging of finished sponge iron is completed in a static state in the combined reaction tank, and the whole process of producing sponge iron is effectively completed by the cold-setting carbon-containing pellets by adopting a method of cooling and reducing the pellets by cold gas, so that the advantages of high reduction speed and high production efficiency of the cold-setting carbon-containing pellets are fully exerted, the three problems of low strength, easy pulverization, adhesion and suspension at high temperature and easy oxidation in the cooling process of the pellets are effectively overcome, and the energy-saving, environment-friendly, efficient, simple and direct sponge iron production device is provided for producing sponge iron by utilizing the cold-setting carbon-containing pellets.

Compared with the prior art, the invention has the following advantages:

1. convenient material transportation, labor saving and time saving. The method of the transportation vehicle loading combined reaction tank for circular transportation is adopted, so that the transportation process is labor-saving, time-saving, simple and smooth.

2. The loading and discharging are convenient, labor-saving and time-saving. The charging and discharging method of the integrated charging and discharging of the combined reaction tank and the lifting device is adopted, so that the charging and discharging work is very convenient and smooth, and the labor and the time are saved.

3. No pulverization and suspension of pellet. The whole reduction process of the carbon-containing pellets in the reduction furnace is finished under the protection of the combined reaction tank, and finished pellets are discharged integrally together with the reaction tank after being cooled, so that the phenomenon of pulverization and suspension is avoided.

4. The energy is saved. The high-temperature pellets after reduction are cooled by cold gas, and the cold gas returns to the gas heating device after recovering the heat in the process of cooling the pellets and is recycled after being heated again, so that the aim of saving energy is fulfilled.

5. Is beneficial to environmental protection. Because the short-flow steelmaking method of sponge iron combined with electric furnace is superior to the long-flow steelmaking method of blast furnace iron-making combined with oxygen-blown converter steelmaking in environmental protection, and because the device adopts the closed-loop circulation of coal gas and the gas-making process without waste liquid discharge, the whole production process is more beneficial to environmental protection.

The following detailed description of embodiments of the invention is made with reference to the accompanying drawings:

referring to figure 1: the figure is a schematic plan view of a reduction system. The whole system is a set of circularly operated interlinked carbon-containing pellet sponge iron production device formed by 12 fixed bed reduction furnaces shown in figure 1 through the connection of heat preservation pipes and the control of a water pressure high-temperature valve, and the device and a pellet transportation device form the cold-setting carbon-containing pellet sponge iron reduction system. The high-temperature coal gas in the system is conveyed by utilizing the coal gas pressure generated by a gasification furnace or arranging a special coal gas fan to drive the coal gas, and the coal gas in the system circularly runs through a gas transmission pipeline lined with refractory materials and externally provided with heat insulation materials, and the coal gas in the system runs by controlling the flow direction, opening and closing of the coal gas by combining a hydraulic cylinder with a high-temperature valve provided with circulating water for cooling. The working procedure and principle of the system are as follows: as shown in the figure, 12 fixed bed reduction furnaces are numbered H1-H12 in sequence, and are input into the H1 reduction furnace through a high-temperature gas branch line input pipeline (2) by a high-temperature gas main conveying pipeline (1) (because of the circulating operation of the high-temperature gas, the furnace is preheated in the early stage, the temperature of pellets reaches about 1000 ℃, the high-temperature gas input again is heated again by a combustion chamber, and then the pellets are cooled againThe temperature can reach about 1400 ℃, under the heating of the high-temperature coal gas, the temperature of the pellets quickly rises to 1150-1200 ℃, so that the solid carbon in the pellets is subjected to direct reduction reaction, namely: because the reaction is carried out in the reducing gas, the reaction speed is very high, and the metallization rate of more than 95 percent can be obtained within 15 minutes. ) Coal gas with the temperature of over 1000 ℃ discharged from the H1 reducing furnace enters the H2 reducing furnace through a communicating pipeline (4) to increase the temperature of pellets in the H2 reducing furnace to over 700 ℃ and promote the pellet temperatureThe pellet is subjected to indirect reduction reaction, namely: at the moment, the H3-H5 reduction furnaces are in a preheating and heating state, and finally, when the temperature of coal gas is reduced to 110-150 ℃, the coal gas is discharged from the H5 reduction furnaces through a coal gas discharge branch pipeline (5), and then the coal gas is carried with gaseous water through a coal gas output main pipeline (6) and is input into a coal gas purification device (7). H in the coal gas is removed by a purifying device (7) and drying devices (8, 9)₂O, S and part of CO₂After being pressurized by a driving fan (10), the cooling gas is continuously input into five reducing furnaces H8-H12 which have completed the reduction process through a cold gas input main pipeline (11) and a cold gas input branch pipeline (12) to cool the high-temperature reduction pellets in the furnaces from low temperature to high temperature, the temperature of the pellets is reduced due to the heat exchange between the cold gas and the high-temperature pellets, the temperature of the gas is increased to about 700 ℃, and finally, circulating gas is input into a circulating gas return main pipeline (14) through a gas output branch pipeline (13) of the H12 reducing furnace and returns to a gas supply system to be heated again for recycling. At the moment, all the processes of reduction, cooling and nitrogen replacement of the H6 and H7 reduction furnaces are completed, and the process enters a loading and unloading stage, wherein a feeding transport vehicle (16) loaded with unreduced pellets is carried to the upper surface of a lower vertical rail (18) of the furnace by a feeding swing vehicle (15) through a feeding swing vehicle rail (17) and enters a loading position of the H6 reduction furnace for loading. Entering into an H7 reducing furnace in a discharging state, similarly, a discharging transport vehicle is conveyed to a track (22) leading to a finished product warehouse through a discharging swing vehicle track (21) through a discharging swing vehicle (19), then enters into the finished product warehouse for discharging, and an empty tank discharging transport vehicle (20) after discharging passes through the track on the swing vehicle, is connected with a reciprocating track (23) through a feeding trackThe channel (3) returns to the loading yard for loading. The direction indicated by the large arrow in the figure is the running direction of the material transporting vehicle and the swing degree vehicle, and the material transporting vehicle and the swing degree vehicle run repeatedly according to the direction, so that a circulating transport line is formed.

Referring to fig. 2: the figure is a cross-sectional view of a single fixed bed reduction furnace of the present invention, the operating principle and embodiment of which are as follows: high-temperature gas from a high-temperature gas supply system enters the combustion chamber through a heat-insulating gas pipeline (1)The chamber (2) is simultaneously used for inputting limited oxygen through the oxygen supply pipe (3) to ensure that small parts of CO and H in the coal gas₂The heat is released by oxidation combustion, the temperature of the coal gas is increased from 1000-1100 ℃ to 1300-1400 ℃, then the coal gas enters a combined reaction tank (4) filled with carbon-containing pellets, enters a reaction chamber (6) through a plurality of downward inclined small holes with the diameter of 6-8 on the pipe wall of a central vent pipe (5), the pellets in the reaction chamber (6) are heated and reduced, then enters a crack gas channel formed by the reaction tank and a furnace chamber (8) through a porous reaction tank outer cylinder (7), and is continuously input into a plurality of reduction furnaces in the next sequence through communicating pipes (12), and the carbon-containing pellets in the furnaces are preheated from high temperature to low temperature and are indirectly reduced at the temperature of 700-1000 ℃. The combined reaction tank can be made of appropriate heat-resistant steel or other ceramic refractory materials, the height of each section is 1-1.5 m, and the number and the diameter of the sections are determined according to the output of a single furnace. The leaf supporting plate (9) is connected with the central vent pipe (5) and is used for supporting the central vent pipe,and the leaf supporting plate and the central vent pipe are separated from the outer barrel in the discharging process so as to smoothly discharge the finished sponge iron which is adhered together due to high-temperature reduction. The reaction pot cover (11) is used for preventing gas from overflowing from the upper opening and has the function of supporting the gas leakage prevention sleeve (10). The reduced high-temperature pellets are cooled by inputting cold gas through a cooling gas input pipe (13). The cooled reduction furnace is composed of N₂The input pipe (14) inputs N₂Performing gas replacement by replacing gas with N₂The gas outlet pipe (15) is discharged and burned. The heat preservation pipe (16) is a heat preservation facility of a heating chamber and a high-temperature pipeline; (17) is a furnace chamber dome; (21) the ash storage chamber is used for storing residual dust brought by coal gas; (22) is a fire-resistant base seat used for supporting the combined reaction tank; (24) is a seal head. The discharging procedure of the reducing furnace is as follows: firstly, the clamping device of the large sealing flange (23) is loosened and slowly released by a windlass (33)The steel ropes fall the tray (25) and the combined reaction tank integrally along the lifting rail (35) arranged on the supporting legs (34) of the furnace body through the pulley block consisting of the fixed pulleys (26, 27, 28) and the movable pulleys (29, 30) and the rail wheels (31, 32), fall on the transport vehicle (38) integrally under the positioning action of the positioning pin (36) and the positioning sleeve (37), and pass through the material conveying rail (39) and the swing vehicle (40) and the swing degreeThe vehicle track (41) is transported to a discharging place. The procedure for charging is the same as that for the same, but in reverse order. The furnace steel plate shell (19) can be manufactured according to the design pressure by adopting the standard ofa boiler steel plate pressing pressure container, and the heat-insulating layer (20) and the fireproof support wall (18) are built by selecting corresponding fireproof materials.

Claims (4)

1. The device for producing the cold-set carbon-containing pellet sponge iron mainly comprises 12 fixed bed reduction furnaces (figure 2) (figure 1, H1-H12), heat-preservation gas pipelines (figure 1-1, 2, 4, 5, 6, 11, 12, 13 and 14), driving fans (figure 1-10), gas purification devices (figure 1-7), gas dryers (figure 1-8 and 9), feeding and discharging swing car tracks (figure 1-17 and 21), longitudinal tracks below the furnaces (figure 1-18), tracks leading to a finished product warehouse (figure 1-22), empty car tracks (figure 1-23), feeding tracks (figure 1-3), swing cars (figure 1-15 and 19), material transporting cars (figure 1-16 and 20) and the like; it is characterized in that a combustion chamber (figure 2-2) is arranged at the top of the fixed bed reduction furnace (figure 2), and the top end of a central vent pipe (figure 2-5) of a combined reaction tank (figure 2-4) arranged in a furnace hearth (figure 2-8) is communicated with a vent hole at the bottom of the combustion chamber (figure 2-2); the charging and discharging of the combined reaction tank (figure 2-4) are lifting devices consisting of pulleys (figure 2-26, 27, 28, 29, 30), trays (figure 2-25), windlasses (figure 2-33), lifting rails (figure 2-35) and lifting rail wheels (figure 2-31, 32), and are lifted integrally from a material conveying vehicle (figure 2-38) together with a sealing large flange (figure 2-23) and a sealing head (figure 2-24) into the furnace at one time, and the sealing is carried out through the sealing large flange (figure 2-23); the discharging of the combined reaction tank (shown in figures 2-4) is to discharge the whole reaction tank after reduction and cooling by adopting the reverse process, and to put the reaction tank on a material conveying vehicle to convey the reaction tank to a finished product warehouse; high-temperature coal gas input by a high-temperature coal gas input pipeline (figure 2-1) enters a first fixed bed reduction furnace, is output by a communicating pipe (figure 2-12) after being heated and reduced, and continuously passes through 5 same fixed bed reduction furnaces to gradually heat pellets in the furnace; when the temperature of the coal gas is reduced to about 110-150 ℃, the coal gas enters a coal gas purification device (shown in figures 1-7) and a coal gas drying device (shown in figures 1-8 and 9) and is used as pellet cooling gas after being purified and dried; after the high-temperature reduction process of part of the reduction furnaces is finished, low-temperature gas is input from a cold gas input header pipe (shown in figures 1-11) through a cooling gas input pipe (shown in figures 2-13) to cool high-temperature pellets in the furnaces, the pellets in the furnaces are continuously cooled step by step through a plurality of reduction furnaces to be cooled, heat in the cooled pellets is also recovered by the cooled gas, the cooled gas returns to a gas supply device through a circulating gas return header pipe (shown in figures 1-14), and the gas is heated … … again, so that the gas is circulated from high temperature to low temperature and from low temperature to high temperature by a production system.

2. The apparatus for producing sponge iron with cold set carbon-containing pellets as claimed in claim 1, wherein the reduction furnace is cooled by coal gas and is discharged by nitrogen gas through a nitrogen gas inlet pipe (fig. 2-14) and a nitrogen gas outlet pipe (fig. 2-15) to realize nitrogen gas replacement, thereby ensuring the safety of discharging.

3. The apparatus forproducing sponge iron with cold-set carbon-containing pellets as claimed in claim 1, wherein the combined reaction tank (fig. 2-4) is composed of an outer cylinder (fig. 2-7) of the reaction tank, a central vent pipe (fig. 2-5) and supporting blades (fig. 2-9); the supporting blade plates (figures 2-9) are integrated with the central vent pipe (figures 2-5) and are separated from the outer cylinder (figures 2-7) of the reaction tank during discharging so as to smoothly pour out the sponge iron which is adhered together in the reduction process.

4. The apparatus for producing sponge iron with cold set carbon-containing pellets as claimed in claim 1, wherein the lower ground of two rows of fixed bed reduction furnaces (fig. 1, H1-H6; H7-H12) arranged in the longitudinal direction is provided with longitudinal rails (fig. 1-18) (fig. 2-39) for the running of the transport vehicle (fig. 2-38) (fig. 1-16, 20), two ends of the longitudinal rails are respectively provided with a groove, and the grooves are internally provided with rails (fig. 1-17, 21) (fig. 2-41) for the running of the swing vehicle. The feeding transport vehicle (figure 1-16) containing carbon-containing pellets is transferred from the upper side of the feeding track (figure 1-3) to the upper side of the lower longitudinal track (figure 1-18) of the furnace under the consignment of the feeding swing car (figure 1-15), and the discharging transport vehicle (figure 1-20) containing finished sponge iron is transferred from the upper side of the lower longitudinal track (figure 1-18) of the furnace to the upper side of the track (figure 1-22) leading to the finished product warehouse under the consignment of the swing car (figure 1-19). The empty can transport vehicles which have unloaded the finished goods in the finished goods warehouse return to the stock ground via the shuttle track (fig. 1-23) and the supply track (fig. 1-3) and are reloaded, thereby forming a circulating transport line.

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